Current perpendicular-to-plane sensors having hard spacers

ABSTRACT

An apparatus according to one embodiment includes a transducer structure having a lower shield and/or an upper shield. A current-perpendicular-to-plane sensor is positioned adjacent the shield(s). An electrical lead layer is positioned between the sensor and the upper or lower shield. The electrical lead layer is in electrical communication with the sensor. A spacer layer is positioned between the electrical lead layer and the upper or lower shield. A conductivity of the electrical lead layer is higher than a conductivity of the spacer layer.

BACKGROUND

The present invention relates to data storage systems, and moreparticularly, this invention relates to magnetic heads, e.g., magnetictape heads, which include current-perpendicular-to-plane (CPP) sensorshaving hard spacers incorporated therewith.

In magnetic storage systems, magnetic transducers read data from andwrite data onto magnetic recording media. Data is written on themagnetic recording media by moving a magnetic recording transducer to aposition over the media where the data is to be stored. The magneticrecording transducer then generates a magnetic field, which encodes thedata into the magnetic media. Data is read from the media by similarlypositioning the magnetic read transducer and then sensing the magneticfield of the magnetic media. Read and write operations may beindependently synchronized with the movement of the media to ensure thatthe data can be read from and written to the desired location on themedia.

An important and continuing goal in the data storage industry is that ofincreasing the density of data stored on a medium. For tape storagesystems, that goal has led to increasing the track and linear bitdensity on recording tape, and decreasing the thickness of the magnetictape medium. However, the development of small footprint, higherperformance tape drive systems has created various problems in thedesign of a tape head assembly for use in such systems.

In a tape drive system, the drive moves the magnetic tape over thesurface of the tape head at high speed. Usually the tape head isdesigned to minimize the spacing between the head and the tape. Thespacing between the magnetic head and the magnetic tape is crucial andso goals in these systems are to have the recording gaps of thetransducers, which are the source of the magnetic recording flux in nearcontact with the tape to effect writing sharp transitions, and to havethe read elements in near contact with the tape to provide effectivecoupling of the magnetic field from the tape to the read elements.

SUMMARY

An apparatus according to one embodiment includes a transducer structurehaving a lower shield. A current-perpendicular-to-plane sensor ispositioned above the lower shield. An electrical lead layer ispositioned between the sensor and the lower shield. The electrical leadlayer is in electrical communication with the sensor. A spacer layer ispositioned between the electrical lead layer and the lower shield. Aconductivity of the electrical lead layer is higher than a conductivityof the spacer layer.

An apparatus according to another embodiment includes a transducerstructure having an upper shield. A current-perpendicular-to-planesensor is positioned below the upper shield. An electrical lead layer ispositioned between the sensor and the upper shield. The electrical leadlayer is in electrical communication with the sensor. A spacer layer ispositioned between the electrical lead layer and the upper shield. Aconductivity of the electrical lead layer is higher than a conductivityof the spacer layer.

Any of these embodiments may be implemented in a magnetic data storagesystem such as a tape drive system, which may include a magnetic head, adrive mechanism for passing a magnetic medium (e.g., recording tape)over the magnetic head, and a controller electrically coupled to themagnetic head.

Other aspects and embodiments of the present invention will becomeapparent from the following detailed description, which, when taken inconjunction with the drawings, illustrate by way of example theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram of a simplified tape drive systemaccording to one embodiment.

FIG. 1B is a schematic diagram of a tape cartridge according to oneembodiment.

FIG. 2 illustrates a side view of a flat-lapped, bi-directional,two-module magnetic tape head according to one embodiment.

FIG. 2A is a tape bearing surface view taken from Line 2A of FIG. 2.

FIG. 2B is a detailed view taken from Circle 2B of FIG. 2A.

FIG. 2C is a detailed view of a partial tape bearing surface of a pairof modules.

FIG. 3 is a partial tape bearing surface view of a magnetic head havinga write-read-write configuration.

FIG. 4 is a partial tape bearing surface view of a magnetic head havinga read-write-read configuration.

FIG. 5 is a side view of a magnetic tape head with three modulesaccording to one embodiment where the modules all generally lie alongabout parallel planes.

FIG. 6 is a side view of a magnetic tape head with three modules in atangent (angled) configuration.

FIG. 7 is a side view of a magnetic tape head with three modules in anoverwrap configuration.

FIG. 8A is a partial side view of a media facing side of a transducerstructure according to one embodiment.

FIG. 8B is a partial side view of a media facing side of a transducerstructure according to one embodiment.

FIG. 9 is a partial side view of a media facing side of a transducerstructure according to one embodiment.

FIG. 10 is a partial side view of a media facing side of a transducerstructure according to one embodiment.

DETAILED DESCRIPTION

The following description is made for the purpose of illustrating thegeneral principles of the present invention and is not meant to limitthe inventive concepts claimed herein. Further, particular featuresdescribed herein can be used in combination with other describedfeatures in each of the various possible combinations and permutations.

Unless otherwise specifically defined herein, all terms are to be giventheir broadest possible interpretation including meanings implied fromthe specification as well as meanings understood by those skilled in theart and/or as defined in dictionaries, treatises, etc.

It must also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an” and “the” include pluralreferents unless otherwise specified.

The following description discloses several preferred embodiments ofmagnetic storage systems having one or more heads which implement CPPsensors having hard spacers incorporated therewith. Thus, variousembodiments described herein may reduce the probability of sensorshorting for CPP sensors, e.g., such as tunneling magnetoresistive (TMR)sensors, giant magnetoresistive (GMR), etc., as will be described infurther detail below.

In one general embodiment, an apparatus includes a transducer structurehaving a lower shield and an upper shield above the lower shield, theupper and lower shields providing magnetic shielding. Acurrent-perpendicular-to-plane sensor is positioned between the upperand lower shields. An electrical lead layer is positioned between thesensor and one of the shields. The electrical lead layer is inelectrical communication with the sensor. A spacer layer is positionedbetween the electrical lead layer and the one of the shields. Aconductivity of the electrical lead layer is higher than a conductivityof the spacer layer.

In another general embodiment, an apparatus includes a transducerstructure having a lower shield and an upper shield above the lowershield, the upper and lower shields providing magnetic shielding. Acurrent-perpendicular-to-plane sensor is positioned between the upperand lower shields. A first electrical lead layer is positioned betweenthe sensor and the upper shield. A second electrical lead layer ispositioned between the sensor and the lower shield. A first spacer layeris positioned between the first electrical lead layer and the uppershield. A second spacer layer is positioned between the secondelectrical lead layer and the lower shield. The first and secondelectrical lead layers are in electrical communication with the sensor.

In yet another general embodiment, an apparatus includes a transducerstructure having a lower shield and an upper shield above the lowershield, the upper and lower shields providing magnetic shielding. Acurrent-perpendicular-to-plane sensor is positioned between the upperand lower shields. An electrical lead layer is positioned between thesensor and one of the shields. The electrical lead layer is inelectrical communication with the sensor. A spacer layer is positionedbetween the electrical lead layer and the one of the shields. A productof the spacer layer thickness multiplied by the conductivity of thespacer layer is less than a product of the electrical lead layerthickness multiplied by the conductivity of the electrical lead layer.

FIG. 1A illustrates a simplified tape drive 100 of a tape-based datastorage system, which may be employed in the context of the presentinvention. While one specific implementation of a tape drive is shown inFIG. 1A, it should be noted that the embodiments described herein may beimplemented in the context of any type of tape drive system.

As shown, a tape supply cartridge 120 and a take-up reel 121 areprovided to support a tape 122. One or more of the reels may form partof a removable cartridge and are not necessarily part of the drive 100.The tape drive, such as that illustrated in FIG. 1A, may further includedrive motor(s) to drive the tape supply cartridge 120 and the take-upreel 121 to move the tape 122 over a tape head 126 of any type. Suchhead may include an array of readers, writers, or both.

Guides 125 guide the tape 122 across the tape head 126. Such tape head126 is in turn coupled to a controller 128 via a cable 130. Thecontroller 128, may be or include a processor and/or any logic forcontrolling any subsystem of the drive 100. For example, the controller128 typically controls head functions such as servo following, datawriting, data reading, etc. The controller 128 may operate under logicknown in the art, as well as any logic disclosed herein. The controller128 may be coupled to a memory 136 of any known type, which may storeinstructions executable by the controller 128. Moreover, the controller128 may be configured and/or programmable to perform or control some orall of the methodology presented herein. Thus, the controller may beconsidered configured to perform various operations by way of logicprogrammed into a chip; software, firmware, or other instructions beingavailable to a processor; etc. and combinations thereof.

The cable 130 may include read/write circuits to transmit data to thehead 126 to be recorded on the tape 122 and to receive data read by thehead 126 from the tape 122. An actuator 132 controls position of thehead 126 relative to the tape 122.

An interface 134 may also be provided for communication between the tapedrive 100 and a host (integral or external) to send and receive the dataand for controlling the operation of the tape drive 100 andcommunicating the status of the tape drive 100 to the host, all as willbe understood by those of skill in the art.

FIG. 1B illustrates an exemplary tape cartridge 150 according to oneembodiment. Such tape cartridge 150 may be used with a system such asthat shown in FIG. 1A. As shown, the tape cartridge 150 includes ahousing 152, a tape 122 in the housing 152, and a nonvolatile memory 156coupled to the housing 152. In some approaches, the nonvolatile memory156 may be embedded inside the housing 152, as shown in FIG. 1B. In moreapproaches, the nonvolatile memory 156 may be attached to the inside oroutside of the housing 152 without modification of the housing 152. Forexample, the nonvolatile memory may be embedded in a self-adhesive label154. In one preferred embodiment, the nonvolatile memory 156 may be aFlash memory device, ROM device, etc., embedded into or coupled to theinside or outside of the tape cartridge 150. The nonvolatile memory isaccessible by the tape drive and the tape operating software (the driversoftware), and/or other device.

By way of example, FIG. 2 illustrates a side view of a flat-lapped,bi-directional, two-module magnetic tape head 200 which may beimplemented in the context of the present invention. As shown, the headincludes a pair of bases 202, each equipped with a module 204, and fixedat a small angle α with respect to each other. The bases may be“U-beams” that are adhesively coupled together. Each module 204 includesa substrate 204A and a closure 204B with a thin film portion, commonlyreferred to as a “gap” in which the readers and/or writers 206 areformed. In use, a tape 208 is moved over the modules 204 along a media(tape) bearing surface 209 in the manner shown for reading and writingdata on the tape 208 using the readers and writers. The wrap angle θ ofthe tape 208 at edges going onto and exiting the flat media supportsurfaces 209 are usually between about 0.1 degree and about 3 degrees.

The substrates 204A are typically constructed of a wear resistantmaterial, such as a ceramic. The closures 204B made of the same orsimilar ceramic as the substrates 204A.

The readers and writers may be arranged in a piggyback or mergedconfiguration. An illustrative piggybacked configuration comprises a(magnetically inductive) writer transducer on top of (or below) a(magnetically shielded) reader transducer (e.g., a magnetoresistivereader, etc.), wherein the poles of the writer and the shields of thereader are generally separated. An illustrative merged configurationcomprises one reader shield in the same physical layer as one writerpole (hence, “merged”). The readers and writers may also be arranged inan interleaved configuration. Alternatively, each array of channels maybe readers or writers only. Any of these arrays may contain one or moreservo track readers for reading servo data on the medium.

FIG. 2A illustrates the tape bearing surface 209 of one of the modules204 taken from Line 2A of FIG. 2. A representative tape 208 is shown indashed lines. The module 204 is preferably long enough to be able tosupport the tape as the head steps between data bands.

In this example, the tape 208 includes 4 to 22 data bands, e.g., with 16data bands and 17 servo tracks 210, as shown in FIG. 2A on a one-halfinch wide tape 208. The data bands are defined between servo tracks 210.Each data band may include a number of data tracks, for example 1024data tracks (not shown). During read/write operations, the readersand/or writers 206 are positioned to specific track positions within oneof the data bands. Outer readers, sometimes called servo readers, readthe servo tracks 210. The servo signals are in turn used to keep thereaders and/or writers 206 aligned with a particular set of tracksduring the read/write operations.

FIG. 2B depicts a plurality of readers and/or writers 206 formed in agap 218 on the module 204 in Circle 2B of FIG. 2A. As shown, the arrayof readers and writers 206 includes, for example, 16 writers 214, 16readers 216 and two servo readers 212, though the number of elements mayvary. Illustrative embodiments include 8, 16, 32, 40, and 64 activereaders and/or writers 206 per array, and alternatively interleaveddesigns having odd numbers of reader or writers such as 17, 25, 33, etc.An illustrative embodiment includes 32 readers per array and/or 32writers per array, where the actual number of transducer elements couldbe greater, e.g., 33, 34, etc. This allows the tape to travel moreslowly, thereby reducing speed-induced tracking and mechanicaldifficulties and/or execute fewer “wraps” to fill or read the tape.While the readers and writers may be arranged in a piggybackconfiguration as shown in FIG. 2B, the readers 216 and writers 214 mayalso be arranged in an interleaved configuration. Alternatively, eacharray of readers and/or writers 206 may be readers or writers only, andthe arrays may contain one or more servo readers 212. As noted byconsidering FIGS. 2 and 2A-B together, each module 204 may include acomplementary set of readers and/or writers 206 for such things asbi-directional reading and writing, read-while-write capability,backward compatibility, etc.

FIG. 2C shows a partial tape bearing surface view of complimentarymodules of a magnetic tape head 200 according to one embodiment. In thisembodiment, each module has a plurality of read/write (R/W) pairs in apiggyback configuration formed on a common substrate 204A and anoptional electrically insulative layer 236. The writers, exemplified bythe write transducer 214 and the readers, exemplified by the readtransducer 216, are aligned parallel to an intended direction of travelof a tape medium thereacross to form an R/W pair, exemplified by the R/Wpair 222. Note that the intended direction of tape travel is sometimesreferred to herein as the direction of tape travel, and such terms maybe used interchangeable. Such direction of tape travel may be inferredfrom the design of the system, e.g., by examining the guides; observingthe actual direction of tape travel relative to the reference point;etc. Moreover, in a system operable for bi-direction reading and/orwriting, the direction of tape travel in both directions is typicallyparallel and thus both directions may be considered equivalent to eachother.

Several R/W pairs 222 may be present, such as 8, 16, 32 pairs, etc. TheR/W pairs 222 as shown are linearly aligned in a direction generallyperpendicular to a direction of tape travel thereacross. However, thepairs may also be aligned diagonally, etc. Servo readers 212 arepositioned on the outside of the array of R/W pairs, the function ofwhich is well known.

Generally, the magnetic tape medium moves in either a forward or reversedirection as indicated by arrow 220. The magnetic tape medium and headassembly 200 operate in a transducing relationship in the mannerwell-known in the art. The piggybacked magnetorisistive (MR) headassembly 200 includes two thin-film modules 224 and 226 of generallyidentical construction.

Modules 224 and 226 are joined together with a space present betweenclosures 204B thereof (partially shown) to form a single physical unitto provide read-while-write capability by activating the writer of theleading module and reader of the trailing module aligned with the writerof the leading module parallel to the direction of tape travel relativethereto. When a module 224, 226 of a piggyback head 200 is constructed,layers are formed in the gap 218 created above an electricallyconductive substrate 204A (partially shown), e.g., of AlTiC, ingenerally the following order for the R/W pairs 222: an insulating layer236, a first shield 232 typically of an iron alloy such as NiFe (−), CZTor Al—Fe—Si (Sendust), a sensor 234 for sensing a data track on amagnetic medium, a second shield 238 typically of a nickel-iron alloy(e.g., ˜80/20 at % NiFe, also known as permalloy), first and secondwriter pole tips 228, 230, and a coil (not shown). The sensor may be ofany known type of CPP sensor, including those based on MR, GMR, TMR,etc.

The first and second writer poles 228, 230 may be fabricated from highmagnetic moment materials such as ˜45/55 NiFe. Note that these materialsare provided by way of example only, and other materials may be used.Additional layers such as insulation between the shields and/or poletips and an insulation layer surrounding the sensor may be present.Illustrative materials for the insulation include alumina and otheroxides, insulative polymers, etc.

The configuration of the tape head 126 according to one embodimentincludes multiple modules, preferably three or more. In awrite-read-write (W-R-W) head, outer modules for writing flank one ormore inner modules for reading. Referring to FIG. 3, depicting a W-R-Wconfiguration, the outer modules 252, 256 each include one or morearrays of writers 260. The inner module 254 of FIG. 3 includes one ormore arrays of readers 258 in a similar configuration. Variations of amulti-module head include a R-W-R head (FIG. 4), a R-R-W head, a W-W-Rhead, etc. In yet other variations, one or more of the modules may haveread/write pairs of transducers. Moreover, more than three modules maybe present. In further approaches, two outer modules may flank two ormore inner modules, e.g., in a W-R-R-W, a R-W-W-R arrangement, etc. Forsimplicity, a W-R-W head is used primarily herein to exemplifyembodiments of the present invention. One skilled in the art apprisedwith the teachings herein will appreciate how permutations of thepresent invention would apply to configurations other than a W-R-Wconfiguration.

FIG. 5 illustrates a magnetic head 126 according to one embodiment ofthe present invention that includes first, second and third modules 302,304, 306 each having a tape bearing surface 308, 310, 312 respectively,which may be flat, contoured, etc. Note that while the term “tapebearing surface” appears to imply that the surface facing the tape 315is in physical contact with the tape bearing surface, this is notnecessarily the case. Rather, only a portion of the tape may be incontact with the tape bearing surface, constantly or intermittently,with other portions of the tape riding (or “flying”) above the tapebearing surface on a layer of air, sometimes referred to as an “airbearing”. The first module 302 will be referred to as the “leading”module as it is the first module encountered by the tape in a threemodule design for tape moving in the indicated direction. The thirdmodule 306 will be referred to as the “trailing” module. The trailingmodule follows the middle module and is the last module seen by the tapein a three module design. The leading and trailing modules 302, 306 arereferred to collectively as outer modules. Also note that the outermodules 302, 306 will alternate as leading modules, depending on thedirection of travel of the tape 315.

In one embodiment, the tape bearing surfaces 308, 310, 312 of the first,second and third modules 302, 304, 306 lie on about parallel planes(which is meant to include parallel and nearly parallel planes, e.g.,between parallel and tangential as in FIG. 6), and the tape bearingsurface 310 of the second module 304 is above the tape bearing surfaces308, 312 of the first and third modules 302, 306. As described below,this has the effect of creating the desired wrap angle α₂ of the taperelative to the tape bearing surface 310 of the second module 304.

Where the tape bearing surfaces 308, 310, 312 lie along parallel ornearly parallel yet offset planes, intuitively, the tape should peel offof the tape bearing surface 308 of the leading module 302. However, thevacuum created by the skiving edge 318 of the leading module 302 hasbeen found by experimentation to be sufficient to keep the tape adheredto the tape bearing surface 308 of the leading module 302. The trailingedge 320 of the leading module 302 (the end from which the tape leavesthe leading module 302) is the approximate reference point which definesthe wrap angle α₂ over the tape bearing surface 310 of the second module304. The tape stays in close proximity to the tape bearing surface untilclose to the trailing edge 320 of the leading module 302. Accordingly,read and/or write elements 322 may be located near the trailing edges ofthe outer modules 302, 306. These embodiments are particularly adaptedfor write-read-write applications.

A benefit of this and other embodiments described herein is that,because the outer modules 302, 306 are fixed at a determined offset fromthe second module 304, the inner wrap angle α₂ is fixed when the modules302, 304, 306 are coupled together or are otherwise fixed into a head.The inner wrap angle α₂ is approximately tan⁻¹(δ/W) where δ is theheight difference between the planes of the tape bearing surfaces 308,310 and W is the width between the opposing ends of the tape bearingsurfaces 308, 310. An illustrative inner wrap angle α₂ is in a range ofabout 0.3° to about 1.1°, though can be any angle required by thedesign.

Beneficially, the inner wrap angle α₂ on the side of the module 304receiving the tape (leading edge) will be larger than the inner wrapangle α₃ on the trailing edge, as the tape 315 rides above the trailingmodule 306. This difference is generally beneficial as a smaller α₃tends to oppose what has heretofore been a steeper exiting effectivewrap angle.

Note that the tape bearing surfaces 308, 312 of the outer modules 302,306 are positioned to achieve a negative wrap angle at the trailing edge320 of the leading module 302. This is generally beneficial in helpingto reduce friction due to contact with the trailing edge 320, providedthat proper consideration is given to the location of the crowbar regionthat forms in the tape where it peels off the head. This negative wrapangle also reduces flutter and scrubbing damage to the elements on theleading module 302. Further, at the trailing module 306, the tape 315flies over the tape bearing surface 312 so there is virtually no wear onthe elements when tape is moving in this direction. Particularly, thetape 315 entrains air and so will not significantly ride on the tapebearing surface 312 of the third module 306 (some contact may occur).This is permissible, because the leading module 302 is writing while thetrailing module 306 is idle.

Writing and reading functions are performed by different modules at anygiven time. In one embodiment, the second module 304 includes aplurality of data and optional servo readers 331 and no writers. Thefirst and third modules 302, 306 include a plurality of writers 322 andno data readers, with the exception that the outer modules 302, 306 mayinclude optional servo readers. The servo readers may be used toposition the head during reading and/or writing operations. The servoreader(s) on each module are typically located towards the end of thearray of readers or writers.

By having only readers or side by side writers and servo readers in thegap between the substrate and closure, the gap length can besubstantially reduced. Typical heads have piggybacked readers andwriters, where the writer is formed above each reader. A typical gap is20-35 microns. However, irregularities on the tape may tend to droopinto the gap and create gap erosion. Thus, the smaller the gap is thebetter. The smaller gap enabled herein exhibits fewer wear relatedproblems.

In some embodiments, the second module 304 has a closure, while thefirst and third modules 302, 306 do not have a closure. Where there isno closure, preferably a hard coating is added to the module. Onepreferred coating is diamond-like carbon (DLC).

In the embodiment shown in FIG. 5, the first, second, and third modules302, 304, 306 each have a closure 332, 334, 336, which extends the tapebearing surface of the associated module, thereby effectivelypositioning the read/write elements away from the edge of the tapebearing surface. The closure 332 on the second module 304 can be aceramic closure of a type typically found on tape heads. The closures334, 336 of the first and third modules 302, 306, however, may beshorter than the closure 332 of the second module 304 as measuredparallel to a direction of tape travel over the respective module. Thisenables positioning the modules closer together. One way to produceshorter closures 334, 336 is to lap the standard ceramic closures of thesecond module 304 an additional amount. Another way is to plate ordeposit thin film closures above the elements during thin filmprocessing. For example, a thin film closure of a hard material such asSendust or nickel-iron alloy (e.g., 45/55) can be formed on the module.

With reduced-thickness ceramic or thin film closures 334, 336 or noclosures on the outer modules 302, 306, the write-to-read gap spacingcan be reduced to less than about 1 mm, e.g., about 0.75 mm, or 50% lessthan commonly-used LTO tape head spacing. The open space between themodules 302, 304, 306 can still be set to approximately 0.5 to 0.6 mm,which in some embodiments is ideal for stabilizing tape motion over thesecond module 304.

Depending on tape tension and stiffness, it may be desirable to anglethe tape bearing surfaces of the outer modules relative to the tapebearing surface of the second module. FIG. 6 illustrates an embodimentwhere the modules 302, 304, 306 are in a tangent or nearly tangent(angled) configuration. Particularly, the tape bearing surfaces of theouter modules 302, 306 are about parallel to the tape at the desiredwrap angle α₂ of the second module 304. In other words, the planes ofthe tape bearing surfaces 308, 312 of the outer modules 302, 306 areoriented at about the desired wrap angle α₂ of the tape 315 relative tothe second module 304. The tape will also pop off of the trailing module306 in this embodiment, thereby reducing wear on the elements in thetrailing module 306. These embodiments are particularly useful forwrite-read-write applications. Additional aspects of these embodimentsare similar to those given above.

Typically, the tape wrap angles may be set about midway between theembodiments shown in FIGS. 5 and 6.

FIG. 7 illustrates an embodiment where the modules 302, 304, 306 are inan overwrap configuration. Particularly, the tape bearing surfaces 308,312 of the outer modules 302, 306 are angled slightly more than the tape315 when set at the desired wrap angle α₂ relative to the second module304. In this embodiment, the tape does not pop off of the trailingmodule, allowing it to be used for writing or reading. Accordingly, theleading and middle modules can both perform reading and/or writingfunctions while the trailing module can read any just-written data.Thus, these embodiments are preferred for write-read-write,read-write-read, and write-write-read applications. In the latterembodiments, closures should be wider than the tape canopies forensuring read capability. The wider closures may require a widergap-to-gap separation. Therefore a preferred embodiment has awrite-read-write configuration, which may use shortened closures thatthus allow closer gap-to-gap separation.

Additional aspects of the embodiments shown in FIGS. 6 and 7 are similarto those given above.

A 32 channel version of a multi-module head 126 may use cables 350having leads on the same or smaller pitch as current 16 channelpiggyback LTO modules, or alternatively the connections on the modulemay be organ-keyboarded for a 50% reduction in cable span. Over-under,writing pair unshielded cables may be used for the writers, which mayhave integrated servo readers.

The outer wrap angles α₁ may be set in the drive, such as by guides ofany type known in the art, such as adjustable rollers, slides, etc. oralternatively by outriggers, which are integral to the head. Forexample, rollers having an offset axis may be used to set the wrapangles. The offset axis creates an orbital arc of rotation, allowingprecise alignment of the wrap angle α₁.

To assemble any of the embodiments described above, conventional u-beamassembly can be used. Accordingly, the mass of the resultant head may bemaintained or even reduced relative to heads of previous generations. Inother approaches, the modules may be constructed as a unitary body.Those skilled in the art, armed with the present teachings, willappreciate that other known methods of manufacturing such heads may beadapted for use in constructing such heads.

With continued reference to the above described apparatuses, it would beadvantageous for tape recording heads to include CPP MR sensortechnology, e.g., such as TMR and GMR. Furthermore, with the continuedreduction of data track widths in magnetic storage technologies, CPP MRsensors enable readback of data in ultra-thin data tracks due to theirhigh level of sensitivity in such small operating environments.

As will be appreciated by one skilled in the art, by way of example, TMRis a magnetoresistive effect that occurs with a magnetic tunneljunction. TMR sensors typically include two ferromagnetic layersseparated by a thin insulating barrier layer. If the barrier layer isthin enough e.g., less than about 15 angstroms, electrons can tunnelfrom one ferromagnetic layer to the other ferromagnetic layer, passingthrough the insulating material and thereby creating a current.Variations in the current, caused by the influence of external magneticfields from a magnetic medium on the free ferromagnetic layer of the TMRsensor, correspond to data stored on the magnetic medium.

It is well known that TMR and other CPP MR sensors are particularlysusceptible to shorting during fabrication due to abrasive lappingparticles that scratch or smear conductive material across theinsulating materials separating the conductive leads, e.g., opposingshields, which allow sense (bias) current to flow through the sensor andmagnetic head as whole. Friction between asperities on the tape and theductile metallic films in the sensor gives rise to deformation forces inthe direction of tape motion. As a result, an electrical short iscreated by the scratching and/or smearing across the layers which has anet effect of creating bridges of conductive material across the sensor.Particularly, the lapping particles tend to plow through ductilemagnetic material, e.g., from one or both shields, smearing the metalacross the insulating material, and thereby creating an electrical shortthat reduces the effective resistance of the sensor and diminishes thesensitivity of the sensor as a whole.

Scientists and engineers familiar with tape recording technology wouldnot expect a CPP MR sensor to remain operable (e.g., by not experiencingshorting) in a contact recording environment such as tape data storage,because of the near certain probability that abrasive asperitiesembedded in the recording medium will scrape across the thin insulatinglayer during tape travel, thereby creating the aforementioned shorting.

Typical CPP MR sensors such as TMR sensors in hard disk driveapplications are configured to be in electrical contact with the top andbottom shields of read head structures. In such configurations thecurrent flow is constrained to traveling between the top shield and thebottom shield through the sensor, by an insulator layer with a thicknessof about 3 to about 100 nanometers (nm). This insulator layer extendsbelow the hard bias magnet layer to insulate the bottom of the hard biasmagnet from the bottom shield/lead layers, and isolates the edges of thesensor from the hard bias magnet material. In a tape environment, wherethe sensor is in contact with the tape media, smearing of the top orbottom shield material can bridge the insulation layer separating thehard bias magnet from the bottom lead and lower shield, thereby shortingthe sensor. Further, shield deformation or smearing can create aconductive bridge across a tunnel barrier layer in a TMR sensor. Suchtunnel barrier layer may be only 12 angstroms wide or less.

In disk drives, conventional CPP MR designs are acceptable because thereis minimal contact between the head and the media. However, for taperecording, the head and the media are in constant contact. Head coatinghas been cited as a possible solution to these shorting issues; howevertape particles and asperities have been known to scratch through and/orwear away these coating materials as well. Furthermore, conventionalmagnetic recording head coatings are not available for protectingagainst defects during lapping processes as the coating is applied afterthese process steps. Because the insulating layers of a conventional CPPMR sensor are significantly thin, the propensity for electrical shortingdue, e.g., to scratches, material deposits, surface defects, filmsdeformation, etc., is high. Embodiments described herein implement novelspacer layers in combination with CPP MR sensors. As a result, some ofthe embodiments described herein may be able to reduce the probabilityof, or even prevent, shorting in the most common areas where shortinghas been observed, e.g. the relatively larger areas on opposite sides ofthe sensor between the shields.

The potential use of CPP MR sensors in tape heads has heretofore beenthought to be highly undesirable, as tape heads include multiplesensors, e.g., 16, 32, 64, etc., on a single die. Thus, if one or moreof those sensors become inoperable due to the aforementioned shorting,the entire head becomes defective and typically would need to bediscarded and/or replaced for proper operation of the apparatus.

Conventional current in-plane type sensors require at least two shortingevents across different parts of the sensor in order to affect thesensor output, and therefore such heads are far less susceptible toshorting due to scratches. In contrast, tape heads with CPP MR sensorsmay short with a single event, which is another reason that CPP MRsensors have not been adopted into contact recording systems.

Various embodiments described herein have top and/or bottom shieldselectrically isolated from a CPP MR sensor, thereby improving thepreviously experienced issue of shield-to-sensor or shield-to-shieldshorting which caused diminished sensor accuracy and/or totalinoperability. Some of the embodiments described herein include spacerlayers which are preferably in close proximity to the sensing structure,thereby resisting deformation and thereby the previously experiencedshorting as well, as will be described in further detail below.

FIG. 8A depicts an apparatus 800, in accordance with one embodiment. Asan option, the present apparatus 800 may be implemented in conjunctionwith features from any other embodiment listed herein, such as thosedescribed with reference to the other FIGS. However, such apparatus 800and others presented herein may be used in various applications and/orin permutations which may or may not be specifically described in theillustrative embodiments listed herein. Further, the apparatus 800presented herein may be used in any desired environment. Thus FIG. 8A(and the other FIGS.) may be deemed to include any possible permutation.

Looking to FIG. 8A, apparatus 800 includes a transducer structure 802which has a lower shield 804 above a wafer 803 and optional undercoat805. Moreover, an upper shield 806 positioned above the lower shield 804(e.g., in a deposition direction thereof). A CPP sensor 808 (e.g. suchas a TMR sensor, GMR sensor, etc.) is positioned between the upper andlower shields 806, 804. As would be appreciated by one skilled in theart, upper and lower shields 806, 804 preferably provide magneticshielding for the CPP sensor 808. Thus, one or both of the upper andlower shields 806, 804 may desirably include a magnetic material of atype known in the art.

FIG. 8A further includes a first electrical lead layer 810 positionedbetween the sensor 808 and the upper shield 806 (e.g., the shieldclosest thereto). Moreover, a second electrical lead layer 812 isincluded between the sensor and the lower shield 804 (e.g., the shieldclosest thereto). The first and second electrical lead layers 810, 812are preferably in electrical communication with the sensor 808, e.g., toenable an electrical current to pass through the sensor 808.

First and second spacer layers 814, 816 are also included in thetransducer structure 802. The spacer layers 814, 816 are dielectric insome approaches, but may be conductive in other approaches. The spacerlayers 814, 816 preferably have a very low ductility, e.g., have a highresistance to bending and deformation in general, and ideally a lowerductility than refractory metals such as Ir, Ta, and Ti. First spacerlayer 814 is positioned such that it is sandwiched between the firstelectrical lead layer 810 and the upper shield 806 (e.g., the shieldclosest thereto). Similarly, the second spacer layer 816 is positionedbetween the second electrical lead layer 812 and the lower shield 804(e.g., the shield closest thereto).

Although it is preferred that a spacer layer is included on either sideof the sensor 808 along the intended direction of tape travel 852, someembodiments may only include one spacer layer positioned between one ofthe leads and the shield closest thereto, such that at least one of theleads, and preferably both leads, are electrically isolated from theshield closest thereto at the tape bearing surface.

As described above, it is not uncommon for tape asperities passing overthe sensor to smear the material of an upper or lower shield onto theopposite shield, thereby potentially shorting the sensor. First andsecond spacer layers 814, 816 reduce the probability of a smearoccurring in the sensor region. Moreover, because the first and secondelectrical lead layers 810, 812 are separated from the upper and lowershields 806, 804 at the tape bearing surface by the first and secondspacer layers 814, 816 respectively, the probability of a smear bridgingthe first and second electrical lead layers 810, 812 is minimized.

Thus, as illustrated in FIG. 8A, it is preferred that the first andsecond spacer layers 814, 816 are positioned at the media facing surface850 of the transducer structure 802, e.g., such that the sensor 808and/or electrical lead layers 810, 812 are separated from the upper andlower shields 806, thereby reducing the chance of a shorting eventoccurring. Moreover, it is preferred that the material composition ofthe first and second spacer layers 814, 816 is sufficiently resistant tosmearing and/or plowing of conductive material across the sensor 808.Thus, the first and second spacer layers 814, 816 are preferably hard,e.g., at least hard enough to prevent asperities in the tape passingover the transducer structure 802 from causing deformations in the mediafacing surface 850 of the transducer structure 802 which effect theperformance of the sensor 808. In preferred embodiments, the firstand/or second spacer layers 814, 816 include aluminum oxide. However,according to various embodiments, the first and/or second spacer layers814, 816 may include at least one of aluminum oxide, chrome oxide,silicon nitride, boron nitride, silicon carbide, silicon oxide, titaniumoxide, ceramics, etc., and/or combinations thereof. Furthermore, invarious embodiments, the first and/or second electrical lead layers 810,812 may include any suitable conductive material, e.g., which mayinclude Ir, Cu, Ru, Pt, NiCr, Au, Ag, Ta, Cr, etc.; a sandwichedstructure of Ta (e.g. Ta/X/Ta); conductive hard alloys such as titaniumnitride, boron nitride, silicon carbide, and the like.

Previously, magnetic heads having aluminum oxide implemented at therecording gap (even amorphous aluminum oxide) were found to have anundesirably low resistance to wear resulting from use, e.g., having amagnetic tape run over the recording gap. Thus, the inventors did notexpect transducer structures 802 having aluminum oxide spacer layers814, 816 to exhibit good performance in terms of resisting smearingand/or plowing caused by tape being run thereover. This idea was furtherstrengthened in view of the lack of materials and/or layers present topromote the growth of crystalline aluminum oxide, the growth of whichwas thereby not supported. However, in sharp contrast to what wasexpected, the inventors discovered that implementing aluminum oxidespacer layers 814, 816 effectively resisted deformation caused by themagnetic tape. Moreover, experimental results achieved by the inventorssupport this surprising result, which is contrary to conventionalwisdom.

Without wishing to be bound by any theory, it is believed that theimproved performance experienced by implementing aluminum oxide spacerlayers 814, 816 may be due to low ductility of alumina, relatively highhardness, and low friction resulting between the aluminum oxide spacerlayers and defects (e.g., asperities) on a magnetic tape being passedthereover. This is particularly apparent when compared to the higherresistance experienced when metal films and/or coating films areimplemented. Specifically, coatings may not be effective in preventingshorting because underlying films (e.g., such as permalloy) are stillsusceptible to indentation, smearing, plowing, deformation, etc.

Thus, in an exemplary approach, the first and/or second spacer layersmay include an aluminum oxide which is preferably amorphous. Moreover,an amorphous aluminum oxide spacer layer may be formed using sputtering,atomic layer deposition, etc., or other processes which would beappreciated by one skilled in the art upon reading the presentdescription. According to another exemplary approach, the first and/orsecond spacer layers may include an at least partially polycrystallinealuminum oxide.

Although first and second spacer layers 814, 816 separate first andsecond electrical lead layers 810, 812 from the upper and lower shields806, 804 at the media facing surface 850 of the transducer structure802, the first and/or second electrical lead layers 810, 812 arepreferably still in electrical communication with the shields closestthereto.

The electrical lead layers 810, 812 may or may not be in electricalcommunication with the associated shield. In approaches where the spacerlayers 814, 816 are insulative, various mechanisms for providing currentto the sensor may be implemented. Looking to FIG. 8A, first and secondelectrical lead layers 810, 812 are in electrical communication with theupper and lower shields 806, 804 respectively, by implementing studs818, 820 at a location recessed from the media facing surface 850.

Studs 818, 820 preferably include one or more conductive materials,thereby effectively providing an electrical via through insulativespacer layers 814, 816 which allows current to flow between the shields806, 804 and electrical lead layers 810, 812, respectively. Thus,although insulative spacer layers 814, 816 may separate the shields 806,804 from the electrical lead layers 810, 812 and sensor 808, the studs818, 820 allow current to flow from one shield to the other through thesensor layer. According to an exemplary in-use embodiment, which is inno way intended to limit the invention, the transducer structure 802 mayachieve this functionality by diverting current from lower shield 804such that it passes through stud 820 (the stud closest thereto) and intothe second electrical lead 812. The current then travels towards themedia facing surface 850 along the second electrical lead 812, andpreferably passes through the tunneling sensor layer 808 near the mediafacing surface 850. As will be appreciated by one skilled in the art,the strength of a signal transduced from the magnetic transitions on amagnetic recording medium decreases along the sensor in the heightdirection (perpendicular to the media facing side). Thus, it ispreferred that at least some of the current passes through the sensorlayer 808 near the media facing surface 850, e.g., to ensure high sensoroutput. According to one approach, this may be accomplished by achievingideally an approximate equipotential along the length of the sensorlayer 808.

Studs 818, 820 preferably have about the same thickness as first andsecond spacer layers 814, 816 respectively. Moreover, studs 818, 820 arepreferably positioned behind or extend past an end of the sensor layer808 which is farthest from the media facing surface 850.

The electrically conductive layer(s) preferably have a higherconductivity than the spacer layer. Thus, the spacer layer in someembodiments may be insulating or a poor conductor. This helps ensurethat a near equipotential is achieved along the length of the sensorlayer. Also and/or alternatively, the resistance of the electrical leadlayer along a direction orthogonal to a media facing surface may be lessthan a resistance across the sensor along a direction parallel to themedia facing surface in some approaches. This also helps ensure that anear equipotential is achieved along the length of the sensor layer. Infurther approaches, the product of the spacer layer thickness multipliedby the conductivity of the spacer layer is less than a product of theelectrical lead layer thickness multiplied by the conductivity of theelectrical lead layer associated with the spacer layer, e.g., positionedon the same side of the sensor therewith.

Achieving near equipotential along the length of the sensor layer 808results in an approximately equal current distribution along the lengthof the sensor layer 808 in the height direction. Thus, if each pointalong the length of the sensor layer 808 had an equal potential for anelectron to tunnel therethrough, the distribution of current would beabout equal as well along the length of the sensor layer 808. Moreover,insulating layer 822 which may include any one or more of the materialsdescribed herein, desirably ensures that current does not flow around(circumvent) the sensor layer 808. Although equipotential is preferredalong the length of the sensor layer 808, a 20% or less difference inthe voltage drop (or loss) across the sensor layer 808 at the mediafacing surface 850 compared to the voltage drop across the end of thesensor layer 808 farthest from the media facing surface 850 may beacceptable, e.g., depending on the desired embodiment. For example, avoltage drop of 1 V across the sensor layer 808 at the media facingsurface 850 compared to a voltage drop of 0.8 V across the end of thesensor layer 808 farthest from the media facing surface 850 may beacceptable.

Although the operating voltage may be adjusted in some approaches tocompensate for differences in the voltage drop along the length of thesensor layer 808 of greater than about 10%, it should be noted that theoperating voltage is preferably not increased to a value above athreshold value. In other words, increasing the operating voltage abovea threshold value is preferably not used to bolster the voltage dropacross the sensor layer 808 at the media facing surface 850 to a desiredlevel (e.g., sensitivity) when a transducer structure 802 has a drop ofgreater than about 10%. The threshold value for the operating voltage ofa given approach may be predetermined, calculated in real time, be setin response to a request, etc. According to an exemplary approach, thethreshold value for the operating voltage may be determined using thebreakdown voltage(s) of the transducer structure 802 layers, e.g., basedon their material composition, dimensions, etc.

In some embodiments, differences in resistivity may also be used tominimize the voltage drop along the length of the sensor layer 808. Inorder to ensure that sufficient current passes through the sensor layer808 near the media facing surface 850, it is preferred that theresistivity of the sensor layer 808, as for example due to tunnelbarrier resistivity in a TMR, is high relative to the resistivity of theelectrical lead layers 810, 812. By creating a difference in therelative resistance of the adjacent layers, low voltage drop maydesirably be achieved along the height of the sensor layer 808.

This relative difference in resistivity values may be achieved byforming the sensor layer 808 such that it has a relatively high barrierresistivity, while the electrical lead layers 810, 812 may have a higherthickness, thereby resulting in a lower resistance value. However, itshould be noted that the thickness of the electrical lead layers 810,812 is preferably greater than about 2 nm. The bulk resistivity of agiven material typically increases as the dimensions of the materialdecreases. As will be appreciated by one skilled in the art upon readingthe present description, the resistivity of a material havingsignificantly small dimensions may actually be higher than for the samematerial having larger dimensions, e.g., due to electron surfacescattering. Moreover, as the thickness of the electrical lead layers810, 812 decreases, the resistance thereof increases. Accordingly, thethickness of the first and/or second electrical lead layers 810, 812 ispreferably between about 2 nm and about 20 nm, more preferably betweenabout 5 nm and about 15 nm, still more preferably less than about 15 nm,but may be higher or lower depending on the desired embodiment, e.g.,depending on the material composition of the first and/or secondelectrical lead layers 810, 812. Moreover, the thicknesses (in thedeposition direction) of the first and/or second spacer layers 814, 816are preferably between about 5 nm and about 50 nm, but may be higher orlower depending on the desired embodiment. For example, spacer layershaving a relatively hard material composition may be thinner than spacerlayers having a material composition which is less hard.

With continued reference to FIG. 8A, studs 818, 820 may be implementedduring formation of the transducer structure 802, using processes whichwould be apparent to one skilled in the art upon reading the presentdescription. According to an example, which is in no way intended tolimit the invention, the spacer layer may be formed over a mask (e.g.,using sputtering or other forms of deposition), thereby creating a voidin the spacer layer upon removal of the mask. Thereafter, the stud maybe formed in the void, e.g., using sputtering or plating, after whichthe stud may be planarized. However, according to another example, aspacer layer may be formed full film, after which a via may be created,e.g., using masking and milling, and filling the via with the studmaterial, e.g., using ALD, after which the stud may optionally beplanarized. Moreover, it should be noted that insulating layer 822 maybe thicker than sensor 808, thereby causing first electrical lead layer810 and first spacer layer 814 to extend in the intended tape traveldirection 852 before continuing beyond the edge of the sensor 808farthest from the media facing surface 850, e.g., as a result ofmanufacturing limitations, as would be appreciated by one skilled in theart upon reading the present description.

Thus, the spacer layers 814, 816 in combination with the studs 818, 820may provide protection against smearing at the media facing surface 850while also allowing for the shields 806, 804 to be in electricalcommunication with the electrical lead layers 810, 812. It follows thatone or both of the shields 806, 804 may serve as electrical connectionsfor the transducer structure 802. According to the present embodiment,the shields 806, 804 function as the leads for the transducer structure802. Moreover, the current which flows towards the media facing surface850 tends to generate a magnetic field which is canceled out by themagnetic field created by the current which flows away from the mediafacing surface 850.

However, it should be noted that the embodiment illustrated in FIG. 8Ais in no way intended to limit the invention. Although the electricallead layers 810, 812 depicted in FIG. 8A are electrically connected toupper and lower shields 806, 804 respectively, in other embodiments, oneor both of the electrical lead layers 810, 812 may not be electricallyconnected to the respective shields. According to one example, the firstand second electrical lead layers may be stitched leads, e.g., see FIG.9, rather than each of the lead layers 810, 812 having a single lead asseen in FIG. 8A, as will soon become apparent. Thus, neither of thefirst or second electrical lead layers may be in electricalcommunication with the shields according to some embodiments, as will bedescribed in further detail below.

FIG. 8B depicts an apparatus 860, in accordance with one embodiment. Asan option, the present apparatus 860 may be implemented in conjunctionwith features from any other embodiment listed herein, such as thosedescribed with reference to the other FIGS. However, such apparatus 860and others presented herein may be used in various applications and/orin permutations which may or may not be specifically described in theillustrative embodiments listed herein. Further, the apparatus 860presented herein may be used in any desired environment. Thus FIG. 8B(and the other FIGS.) may be deemed to include any possible permutation.

In FIG. 8B, only a single hard spacer layer 814 is present. In thisembodiment, the hard spacer layer 814 is between the sensor 808 and theupper shield 806. A conductive conventional spacer layer 862 is presentbetween the sensor 808 and the lower shield 804.

In other embodiments, a single hard spacer layer may be present belowthe sensor 808.

Looking to FIG. 9, apparatus 900 depicts a transducer structure 902 inaccordance with one embodiment. As an option, the present apparatus 900may be implemented in conjunction with features from any otherembodiment listed herein, such as those described with reference to theother FIGS. Specifically, FIG. 9 illustrates variations of theembodiment of FIG. 8A depicting several exemplary configurations withinthe transducer structure 902. Accordingly, various components of FIG. 9have common numbering with those of FIG. 8A.

However, such apparatus 900 and others presented herein may be used invarious applications and/or in permutations which may or may not bespecifically described in the illustrative embodiments listed herein.Further, the apparatus 900 presented herein may be used in any desiredenvironment. Thus FIG. 9 (and the other FIGS.) may be deemed to includeany possible permutation.

Looking to FIG. 9, apparatus 900 includes a transducer structure 902having spacer layers 814, 816 sandwiched between shields 806, 804 andelectrical lead layers 904, 906 respectively. However, unlike theembodiment illustrated in FIG. 8A, first and second electrical leadlayers 904, 906 of the present embodiment may not be in electricalcommunication with either of the shields 806, 804. Rather, when thespacer layers 814, 816 are insulating and fully isolate electrical leadlayers 904, 906 from upper and lower shields 806, 804 respectfully alongthe lengths (perpendicular to the media facing surface 850) thereof.Thus, a current (e.g., a read sense current) does not pass through atleast one of the upper and lower shields from the CPP sensor 808 and/orelectrical lead layers 904, 906. In other words, the electricalconnection to one or both of the electrical lead layers 904, 906 may beindependent. As mentioned above, first and/or second spacer layers 814,816 may include at least one of aluminum oxide, chrome oxide, siliconnitride, boron nitride, silicon carbide, silicon oxide, titanium oxide,an amorphous aluminum oxide, etc., and/or combinations thereof, andconducting but non-smearing materials such as titanium nitride,conductive ceramics, etc.

According to some approaches, the at least one of the upper and lowershields 806, 804 not having a current (e.g., a read sense current)passing therethrough may be coupled to a bias voltage source. In otherwords, at least one of the upper and lower shields 806, 804 may becoupled to a bias voltage source. According to other approaches, one orboth of the shields may be coupled to an electrical connection (e.g., alead), but may not carry any current therethrough.

As mentioned above, at least one of the first and second electrical leadlayers may be a stitched lead. According to the present embodiment,which is in no way intended to limit the invention, both electrical leadlayers 904, 906 are stitched leads which include a main layer 908, 910and a preferably thicker stitch layer 912, 914 thereon, respectively.Vias 913, 915 may be coupled to a respective electrical lead layer 904,906. The main layers 908, 910 may be made during formation of thetransducer structure 902, while stitch layers 912, 914 may be drilledand backfilled after formation of the transducer structure 902 usingprocesses and/or in a direction which would be apparent to one skilledin the art upon reading the present description.

As shown, the stitch layers 912, 914 are preferably recessed from amedia facing side of the main layer 908, 910, e.g., the side closes tothe media facing surface 850. By stitching a second layer of leadmaterial, e.g. the stitch layer 912, 914, which is preferably recessedbeyond a back edge 916 of the sensor 808 in the height direction H, theresistance associated with the electrical lead layers 904, 906 maydesirably be reduced, e.g., relative to routing either of the leads pasta back edge of the respective shield. In various embodiments, the mainlayers 908, 910 and/or a stitch layers 912, 914 of either of thestitched electrical lead layers 904, 906 may be constructed of anysuitable conductive material, e.g., which may include Ir, Cu, Ru, Pt,NiCr, Au, Ag, Ta, Cr, etc.; a laminated structure of Ta (e.g. Ta/X/Ta);etc.

As mentioned above, the stitched electrical lead layer configurationimplemented in transducer structure 902 desirably reduces the resistanceassociated with the routing either of the leads beyond a back edge ofthe respective shield. For example, in an embodiment where Ru is used asthe top lead material, the resistivity “p” would be about 7.1micro-ohms/cm. A single lead with thickness of 30 nm would have a sheetresistivity (ρ/thickness) equal to about 2.3 ohms/square. This impliesthat if the top lead design had 6 “squares” of lead geometry, the leadresistance would be about 13.8 ohms. However, by implementing a stitchedlayer above the main layer of the stitched electrical lead layer, thetotal lead resistance would be significantly reduced. For example,consider a stitched lead of Ru with a thickness of 45 nm covering 5 ofthe 6 “squares” of the lead geometry. The lead region where the stitchedstructure and the initial lead overlay has a net thickness of about 75nm and a sheet resistivity equal to 0.95 ohms/square. Implementing astitched electrical lead layer as described above would reduce the leadresistance to 7.3 ohms or by about 45%. Embodiments described herein mayor may not implement the stitched electrical lead layers 904, 906 (e.g.,see FIG. 8A), depending on the preferred embodiment.

In still further approaches, one or more of the electrical lead layersmay be an extension of a layer itself, or a separately-depositedmaterial. Establishing an electrical connection to a magnetic laminationproximate to the sensor may create a configuration in which portions ofthe magnetic shields of an apparatus are not biased or current-carrying.In such embodiments, the electrical lead layers included between thesensor structure and the magnetic shield may serve as an electricallead. Moreover, at least one of the upper and lower shields 806, 804 maybe a floating shield, and thereby may not be biased or current-carrying.

FIG. 10 depicts an embodiment 1000 which includes vias 913, 915 likethose of FIG. 9, and studs 818, 820 like those in FIG. 8A. The studs818, 820 are not current carrying and therefore preferably have arelatively high resistance compared to the current-carrying portions ofthe head.

Various embodiments described herein are able to provide bi-directionalprotection for CPP transducers against shorting which may otherwiseresult from passing magnetic media over such transducers. Implementing aspacer layer having a high resistivity to smearing and/or plowingbetween the CPP transducer layer and each of the conducting leadportions of the transducer stack without hindering the flow of currentthrough the sensor enables the embodiments herein to maintain desirableperformance over time. Moreover, as previously mentioned, although it ispreferred that an spacer layer is included on either side of a sensoralong the intended direction of tape travel, some of the embodimentsdescribed herein may only include one spacer layer positioned betweenone of the leads or sensor and the shield closest thereto, such that theat least one lead is electrically isolated from the shield closestthereto.

Various embodiments may be fabricated using known manufacturingtechniques. Conventional materials may be used for the various layersunless otherwise specifically foreclosed. Furthermore, as describedabove, deposition thicknesses, configurations, etc. may vary dependingon the embodiment.

It should be noted that although FIGS. 8-9 each illustrate a singletransducer structure (transducer structures 802, 902), variousembodiments described herein include at least eight of the transducerstructures above a common substrate, e.g., as shown in FIG. 2B.Furthermore, the number of transducer structures in a given array mayvary depending on the preferred embodiment.

It will be clear that the various features of the foregoing systemsand/or methodologies may be combined in any way, creating a plurality ofcombinations from the descriptions presented above.

It will be further appreciated that embodiments of the present inventionmay be provided in the form of a service deployed on behalf of acustomer.

The inventive concepts disclosed herein have been presented by way ofexample to illustrate the myriad features thereof in a plurality ofillustrative scenarios, embodiments, and/or implementations. It shouldbe appreciated that the concepts generally disclosed are to beconsidered as modular, and may be implemented in any combination,permutation, or synthesis thereof. In addition, any modification,alteration, or equivalent of the presently disclosed features,functions, and concepts that would be appreciated by a person havingordinary skill in the art upon reading the instant descriptions shouldalso be considered within the scope of this disclosure.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of an embodiment of the presentinvention should not be limited by any of the above-described exemplaryembodiments, but should be defined only in accordance with the followingclaims and their equivalents.

1. An apparatus, comprising: a transducer structure having: a lowershield; a current-perpendicular-to-plane sensor above the lower shield;an electrical lead layer between the sensor and the lower shield,wherein the electrical lead layer is in electrical communication withthe sensor; and a spacer layer between the electrical lead layer and thelower shield, wherein a conductivity of the electrical lead layer ishigher than a conductivity of the spacer layer.
 2. An apparatus asrecited in claim 1, comprising a second electrical lead layer presentbetween the sensor and an upper shield, wherein a second spacer layer ispresent between the upper shield and the second electrical lead layer.3. An apparatus as recited in claim 1, wherein the spacer layer includesat least one material selected from a group consisting of: aluminumoxide, chrome oxide, silicon nitride, boron nitride, silicon carbide,silicon oxide, titanium oxide, and titanium nitride.
 4. An apparatus asrecited in claim 1, wherein the spacer layer includes an aluminum oxideselected from a group consisting of: amorphous aluminum oxide and atleast partially polycrystalline aluminum oxide.
 5. An apparatus asrecited in claim 1, wherein the electrical lead layer includes a mainlayer and a stitch layer, the stitch layer being recessed from a mediafacing side of the main layer.
 6. An apparatus as recited in claim 1,wherein a resistance of the electrical lead layer along a directionorthogonal to a media facing surface is less than a resistance acrossthe sensor along a direction parallel to the media facing surface.
 7. Anapparatus as recited in claim 1, wherein spacer layer is electricallyconductive.
 8. An apparatus as recited in claim 1, wherein spacer layeris electrically insulating.
 9. An apparatus as recited in claim 1,wherein the electrical lead layer is in electrical communication withthe lower shield.
 10. An apparatus as recited in claim 1, wherein theelectrical lead layer is not in electrical communication with the lowershield.
 11. An apparatus as recited in claim 1, comprising: a drivemechanism for passing a magnetic medium over the sensor; and acontroller electrically coupled to the sensor.
 12. An apparatus,comprising: a transducer structure having: an upper shield; acurrent-perpendicular-to-plane sensor below the upper shield; anelectrical lead layer between the sensor and the upper shield, whereinthe electrical lead layer is in electrical communication with thesensor; and a spacer layer between the electrical lead layer and theupper shield, wherein a conductivity of the electrical lead layer ishigher than a conductivity of the spacer layer.
 13. An apparatus asrecited in claim 12, wherein the spacer layer includes at least onematerial selected from a group consisting of: aluminum oxide, chromeoxide, silicon nitride, boron nitride, silicon carbide, silicon oxide,titanium oxide, and titanium nitride.
 14. An apparatus as recited inclaim 12, wherein the spacer layer includes an aluminum oxide selectedfrom a group consisting of: amorphous aluminum oxide and at leastpartially polycrystalline aluminum oxide.
 15. An apparatus as recited inclaim 12, wherein the electrical lead layer includes a main layer and astitch layer, the stitch layer being recessed from a media facing sideof the main layer.
 16. An apparatus as recited in claim 12, wherein aresistance of the electrical lead layer along a direction orthogonal toa media facing surface is less than a resistance across the sensor alonga direction parallel to the media facing surface.
 17. An apparatus asrecited in claim 12, wherein spacer layer is electrically insulating.18. An apparatus as recited in claim 12, wherein the electrical leadlayer is in electrical communication with the upper shield.
 19. Anapparatus as recited in claim 12, wherein the electrical lead layer isnot in electrical communication with the upper shield.
 20. An apparatusas recited in claim 12, comprising: a drive mechanism for passing amagnetic medium over the sensor; and a controller electrically coupledto the sensor.